After reading yesterday's post about why Linkedin users need to put some contact info on their Linkedin profiles, a Big Apple correspondent asked me why I didn't mention Inmail.
Simple. Most Linkedin users have the free account and aren't willing to pay extra to send Inmail via Linkedin.
Personally, I think Linkedin has made a big mistake by not enabling free messaging between all Linkedin account holders as Facebook has done. In Facebook, you have to opt out or use your account settings to place restrictions on who can send you a message via Facebook. On Linkedin you have to opt in - and it costs you.
See my September 1 2010 post about how Linkedin's stubborn refusal to become more like Facebook in this one regard has, in my opinion, retarded Linkedin's growth and allowed Facebook to siphon off professional and business users who should be using Linkedin more and Facebook less. With Linkedin's superior search capabilities and business conscious demographic, business and professional users would undoubtedly use Linkedin much more than they already do if they could send messages to other Linkedin users who are outside their networks.
To summarize, unless you pay for Linkedin's branded "Inmail" messaging, you cannot send a message to Linkedin users who are outside your network. In other words, you can message 1st-level connections and you can message members of the groups you belong to so in addition to putting actual contact info on your profile you should also join groups and start sending connection requests to other Linkedin users.