Requests for a "Serial Number for Adobe Illustrator CS5 Extended" often stem from a confusion between Photoshop’s naming conventions and Illustrator’s feature sets.
Here is a blog post draft that focuses on the legacy of Illustrator CS5 and how activation works for those who still own it. Serial Number Adobe Illustrator Cs5 Extended
Websites like 4shared, Pastebin, or random blogs publish lists like: 1325-1551- ... Requests for a "Serial Number for Adobe Illustrator