Due to the way some plugins work (such as Pretty Link, but not exclusively restricted to them) when people are transitioning to ThirstyAffiliates they run into issues with the URLs requiring a Link Prefix.
Our plugin was built to avoid the URL clashing problems that are commonly seen with Pretty Link and other similar plugins.
As an example of the issue in these other plugins is the ability to create a link similar to http://example.com/my-link
That is fine until you make a post titled My Link which will use that same slug. So you end up with a URL clash and some really funky stuff can happen depending on your server setup!
Our plugin forces a Link Prefix which gets around the issue of URL clashes completely and results in a more friendly URL.
The good news for you is that doesn't stop you putting in redirects to solve the issue of maintaining those old URLs.
In fact, in some installations we've seen, if you don't have a post URL that is similar to your link's URL WordPress itself is smart enough to work it out and will actually automatically redirect the URL for you to the ThirstyAffiliates link.
So there are three options:
1. Import your links into ThirstyAffiliates and test the old URLs to see if they automatically redirect.
2. Run a text replacement plugin like (Text Replace o Search & Replace) to replace old link URLs across your content with the new ones. This is a manual process but something you only have to do once thankfully.
3. Use something like Redirección plugin which will let you make a CSV file with your old link in one column and your new link in the next column that you can upload and it will create all the redirects for you.
If you have mentions of your links outside of your WordPress installation (eg. some people have them inside email autoresponders) we recommend 1. or 3. to reduce your admin overhead. 3. would be a more reliable solution which is important as we're dealing with an income source.
Any questions on this, please contact us at the support forum or if you're a ThirstyAffiliates Pro license holder via the Support page.