[Shermy]

His signature maybe?

Several of the deletes appear to be his signature. But many are certainly not.

[nuffsenuff]

Some are probably signatures, some may be names of his victims, some might be the names of groups he admired (terrorist groups)...

The guy is obviously a terrorist sympathizer... That's got to be pretty clear by now.

[Sacajaweau]

Might be a little code name rather than his ordinary signature.