Bonko9:
I am putting most effort on saved ebay searches rather than specific sellers. I have set up a list of key words and also narrowed it down with sizes etc. It means I get like 100 search hits to my email every day or so. I think that covers things pretty well. Obviously you are missing out on some, but thats hard to avoid.
With facebook, I did that for a while, but most of the time any jerseys I would be interested in sold within 2 hours of being listed and I got tired of it :-) Also its nice to get a break from the jersey collecting while browsing facebook, haha.