Theoretically, there is no limit to the number of links that the Links script can handle. The limit is entirely based on your server space.

Practically speaking, it would not be a good idea to use Links in its current configuration with that many entries because it would really run slow, especially when building the pages and doing searches. With that many links, it would be necessary to change the type of database used to run it, something like SQL, instead of a flat-file database.

To his credit, Alex is aware of that limitation and has promised an SQL-based version of Links to be released sometime in the near future.

I hope this answers your question.