In the trend of algorithm updates in 2025, the underlying logic of link building has become clear, focusing on two core principles: Indexing Rate Priority Based on Quantity and Natural Anchor Text Distribution.
Real-world data shows that unindexed backlinks have almost no ranking value, while continuously adding a large number of easily indexable regular backlinks (including nofollow) tends to trigger algorithmic “ranking boosts” more effectively than a small number of high-authority links.
When it comes to cost control, backlink quality isn’t just determined by DA score.
Data shows that forums with DA > 1 already have basic ranking influence. In the industry, once the cost of a single backlink exceeds 80 RMB, its ROI usually decreases as DA increases.
In the 2025 backlink strategy, it’s far more effective to prioritize over 300 diversified indexable links than to chase a few expensive resources.
Basic Working Mechanism of Forum Signature Backlinks
The core requirement for search engines to crawl backlinks is that the links themselves must be indexed—signature backlinks that aren’t indexed (whether nofollow or not) basically don’t pass any value.
The real key isn’t the “quality” of a single backlink, but the total number of indexed links.
Once signature links exceed 200 and are being crawled consistently, algorithms tend to view the source as having a “user-recommended” nature, thereby activating basic ranking signals.
Hidden Rule in the Source Code: Placement Determines Crawling Priority
When search engine bots crawl web pages, the position of a signature backlink in the HTML directly affects its likelihood of being crawled. For example:
- Main Content Area: If the signature is placed within the user’s reply (rather than in a fixed footer template), bots usually treat it as “user-generated content,” increasing the indexing rate to over 40% (based on 2023 testing).
- Collapsed Footer Area: Some forums hide signatures behind “click to expand” sections, meaning the links only load after user interaction. Bots generally ignore these, with an indexing rate below 5%.
- Duplicate Trap: If the same page shows many user signatures (like on forum lists), only the first 3 signature links are typically crawled; others are seen as redundant.
Actionable Tips:
- Pick forums that allow signatures inside the reply area (such as Discuz! X3.4 and above).
- Avoid using JS-loaded signature sections; stick to plain text or basic HTML links.
nofollow ≠ Useless: 3 Conditions for Passing Value
Even though nofollow tags block direct link juice, links can still impact SEO indirectly under these conditions:
| Condition | How It Works | Example |
|---|---|---|
| High Page Engagement | Users stay on the page for more than 90 seconds and click the link | Bots associate user behavior data with the link |
| Relevant Link Context | The text around the backlink matches the target page’s topic | Placing a building materials link in a home renovation discussion |
| Continuously Updated Source Page | The post containing the signature gets new interactions every month | The thread owner keeps replying to bump the thread |
Forum Authority ≠ Link Authority: The Overlooked “Voting Power” Rule
High-traffic forums don’t necessarily offer stronger signature backlinks. The effectiveness mainly depends on:
- Backlink Indexing Volume: A forum with lots of indexed posts and basic authority often beats a high-traffic post with few indexed backlinks.
- User Interaction Quality: 10 genuinely discussed posts outperform 100 spammy posts with backlinks.
- Link Lifespan: Signature backlinks that stay live for over 6 months can double in value—up to 120% ranking power increase.
For example, a small niche forum with DA > 1 but over 300 indexed posts can outperform a large DA 40 portal in backlink impact.
Anchor Text “Naturalness” Warning Line
- Risky Practice: Over 30% of signature links in the same forum using exact-match keyword anchors (like “Beijing rental platform”).
Safe Strategy: Mix Brand Names (30%) + Generic Terms (50%) + Naked URLs (20%).
Example:
- Brand Name: XX Home Renovation Official Site
- Generic Terms: Click to learn more / Check details
- Naked URL: http://www.xxx.com
Hidden Value of nofollow Links
Unindexed links (whether nofollow or not) are practically useless, but once a site accumulates over 500 indexed nofollow links,
The algorithm may treat it as a “natural recommendation” signal, indirectly boosting ranking power.
User Behavior Data
Search engines assess the value of nofollow links based on user behavior signals, including:
Time on Page > 90 Seconds: If users click a nofollow link and stay on the target page for longer than this threshold, search engines will recognize the link as having “recommendation value.”
In a 2023 test by an education agency, nofollow backlinks meeting this condition led to a 32% ranking boost for target pages.
Second Click Rate > 15%: When users click multiple links (including nofollow ones) within the same source page (like a forum post), the algorithm connects these links’ topics.
For example, in a post about studying abroad, if users click both “study abroad agency” and “language training” nofollow links, this strengthens the topical relationship between the two pages.
Practical Tips:
- Place backlinks in tutorial or controversial topic posts (these naturally have longer user engagement).
- Design landing pages with content that encourages users to explore deeper (like comparisons, reviews, or case studies).
Anchor Text Diversity
Over-optimizing anchor text is the main reason why nofollow backlinks lose effectiveness. Here’s a proven strategy for distributing anchor text types:
| Anchor Text Type | Proportion | Example | Purpose |
|---|---|---|---|
| Generic Terms | 65% | “Click here”, “Official Site” | Lower the risk of algorithm penalties |
| Brand Terms | 25% | “New Oriental Study Abroad” | Boost brand search visibility |
| Plain URLs | 10% | http://www.xxx.com | Simulate natural link sharing |
High-Risk Red Lines:
- Using the same anchor text more than 3 times within the same forum (this triggers “template-like backlink” detection)
- Using industry-specific keywords in unrelated topic sections (for example, posting a “TOEFL training” link in a food forum)
Case Study:
A travel website posted nofollow backlinks in a photography forum using a chain of anchor texts like “Photography Guide → Scenic Spot Photos → Official Site,” which increased their organic traffic by 18% with no risk warnings.
Scale Effect of Backlinks with DA > 1
There’s a common misunderstanding in the industry about blindly chasing high DA backlinks:
| DA Range | Cost Per Link (CNY) | Effective Quantity | Cost-Effectiveness Rating |
|---|---|---|---|
| 1-10 | 20-50 | Effective from 500 links | ★★★★☆ |
| 11-30 | 60-100 | Effective from 300 links | ★★☆☆☆ |
| 30+ | 120-300 | Effective from 100 links | ★☆☆☆☆ |
Key Takeaways:
- Forum backlinks with DA > 1 already provide basic traffic-driving power and cost less than their return threshold (cost per unique visitor < 1 CNY)
- Deploying 10,000 DA > 1 backlinks (about 5,000 CNY total) significantly boosts site authority—far outperforming 100 DA > 30 backlinks (about 15,000 CNY total)
Execution Strategy:
- Use crawler tools to bulk-scrape active forums related to long-tail keywords (forums with over 100 daily posts)
- Prioritize sections that allow signature links and have lenient moderation (such as “Community Interaction” boards)
Algorithm Logic: 3 Layers of Nofollow Link Influence
- Trust Accumulation: When a site has 500+ indexed nofollow links from the same domain, Google tends to treat these backlinks as “non-manipulative”
- Semantic Relevance Enhancement: Keywords surrounding the nofollow link (like “cost-effective” or “review”) help Google better understand the linked page
- Cross-Platform Synergy: When social media (with nofollow links) and forum backlinks both point to the same page, ranking improves up to 40% faster
There are no shortcuts in SEO, but the right methods can make the path much shorter.
