I know gog likely needs no help on getting the word out about their site and sales model but I thought it might be good to list ideas you have used to spread the gog on the net.
1. I have gone to forum sites and talked up gog many times.
2. I have gone to Amazon.com and directed people to this site.
3. I have also used the "Contact" link on sites that sell games mentioning gog to them as a way to expose their games to a wider audience and maybe increase sales.
I always mention the $5.99 or $9.99 price structure and of course the fact that ALL gog titles are DRM Free.
The most recent one I contacted was Reflexive, makers of Ricochet Lost Worlds and other Ricochet games.
These are some of the most enjoyable "Breakout" style games I have ever played. Very fun and very innovative.
I would love to see them available here on gog.
So, go Spread some gog! :o)

I added a GOG link to my signature on every forum I frequent. I know most people ignore sigs, but it may attract a few.

I talk about it with people I work with. We're all a helpful bunch, I figure the more helpful people on here, the better.

I've also spread the word about GOG. Most people don't seem to share our enthusiasm though, but I figure it never hurts to let them know a haven for classics exists!

I've also placed it on my forum thread signature but a also thinking of getting a tattoo, not sure though. Only place people are gonna see it is on my forehead...... 'cause it's so damned big.

You know it would be great is gog would create and slick looking Sig that people could download and use to promote the site.

Hey gog, how about making some nice looking Avatars the support the various games here on gog, or some straight out gog Avatars the game one could have a gog banner across the bottom?

Not sure about all the games on GOG, but at least a few of the ones I've bought do come with avatars as part of the bonus content.

I think I can get in trouble for "advertising" in sigs at gamefaqs, which is the only forum system I browse with any regularity.
I do, however, bring it up when appropriate.

Have lots of unprotected sex.

Don't you think, that GOG should focus on traditional "box" games, rather than on casuals? These games you may purchase for no more than 19$ (from Big Fish Games even for 6$). I think that GOG should focus on games, that are no more available for purchase (classics from the 90s'). :)

You know that is a valid point and I honestly never looked at it from that angle. I do think however, that a wider array of games is a good thing. Also, the games I mentioned are not on those sites I do not think, nor do I want a client of some nature to play games like these on my computer.
In the end though, your view will likely be the course of action. :o)

I tell everyone I know that loves gaming like me, or put it in my profiles on other sites I visit. This is a great site.

They also made Lionheart: legacy of the crusader ;)