Since few contacts through PM are asking on how was the domain advertised to attract a serious buyer, I will just share some details.
1. I contacted the brokers that handled the social.com domain but they seemed slow and not so enthusiast as I was on the potential of this domain. A good broker is a good starting point, but there are few enthusiast good brokers around.
2. Created a for-sale page (it can be still be seen (sep 15th) on Google cache) and started advertisting the domain myself.
Advertising included 5-10 twitter messages. I created an account that RT any #domain tweet. Got almost 200 followers. I asked "friends" on twitter to RT 1-2 my message about this specific domain which was for sale.
3. I decided that I would not sell the domain unless I get 20K$. I rejeceted any lower offer. I suggest the price to some potential-buyers that contacted me with sums in the x,xxx$ range. They actually rejected my 20K$ offer.
4. Even if I received the first 50K$ offer I had to be sure that I had a serious buyer. I received a 100K$ offer by email but turned out to be not a real offer.
5. Contacted domains@{google, facebook, microsoft}. After rumors from the socl.com domain linked to Microsoft I even contacted some domain agent that works for Microsoft via LinkedIn. There was no reply in the emails and the lady from Microsoft was nice to inform me that they have no interest on the domain via LinkedIn.
From the first moment of the accepted offer from the client, until the final domain transfer was a period of 2 months.
Endline, I guess I did not do something unusual from what other enthusiasts with a good domain do. I just fixed a price and waited patiently for the right buyer to come.
In the worst case, I had a domain I loved.