Google used to recommend that “keep the links on a given page to a reasonable number (fewer than 100)”. So why did Google provide such recommendation?
The original reason for this recommendation is that Google used to index only about 100 kilobytes of a page. If a page started to have more than that, there was a chance that the page would be too long and Google wouldn’t index the entire page.
Is this guideline still valid?
The short answer is no, the number of links Google can process on a page is now much larger. Bear in mind that if you have too many links on a page, the amount of link juice blowing out on each individual link can become very small. Google is also willing to take action on spammy links.