MacSparky posted a slick little trick on how to use TextExpander to insert just the link (no http:\www.blahblah.com) in the signature line. Another nice trick with TextExpander is to use it to insert a signature, literally, into Pages, Word or Open Office documents.
Scan your signature and open in Adobe or Preview. Next, use OS X’s built in screen clipping (shift-command-4) key stroke to clip the signature. Open clipped signature in Preview. Once open in preview, click and hold the little arrow on the select toolbar icon. Choose ‘Instant Alpha.’
Then, click and drag away the white portions around the signature. This step is necessary so that you aren’t pasting a white block/rectangle into your documents. By erasing the back ground, the text or signature line in the document will still show through the signature. Save the signature as a PNG file with the ‘alpha’ box checked.
Create a Snippet
Open TextExpander and create a new snippet with Content: Formatted Text, Pictures from the dropdown.
Click on the plus arrow and choose insert “Picture.” Choose the file you saved for the signature.
Now, whenever you type your shortcut, your signature will be dropped into the document.