Frank Herbert opened his classic "Dune" with this line: "A beginning is a delicate time."  That applies to recruiting all the time.  There are few roles out there that require meeting strangers on such a regular basis. In this, and in other areas, we are close cousins to sales people.

It used to be fairly standard. You had a phone, a job order, and some means of keeping notes.  You'd get comfortable with the job order, and compare it to your stack of candidates (back when I started, that was a literal stack - of paper). You'd reach out to the closest matches, discuss the role, and either present them to the client if it made sense, or get referrals from them of people who might be better fits. You'd also be calling people who weren't active, but that you had some contact with in the past, and asking similar questions. The second bit - the referrals - meant introducing yourself to a lot of strangers.

This still goes on - now it's a database of people you keep track of, and the way you talk to your network may be as much by phone as it is electronic (from e-mail to DMing on Twitter, etc). The key thing is, when it's not over the phone or in person, how personal your introduction becomes.  If you approach a stranger and invite them to join one of your social networks, do you use the script that was left in by the service (because, "[a stranger] would like to be in your network" sounds so compelling)? If you don't, give yourself a pat on the back. If you use the generic intro, stop that.  Seriously - you're losing a golden time to make a good impression, and increasing your chances of them actually accepting the invite.  Which is kinda the point of the invite going out. Don't lose all that sourcing time because you didn't want to spend a minute personalizing.

Now: what about Twitter? It's easy to follow someone there. If their network's big enough, they won't even notice the follow.  Does it make sense to let them know?

That's murkier. Hardly anyone does it, and it might seem a bit presumptuous, but as a way to get someone's eyes on you it's pretty good.  As social media analyst Jeremiah Owyang (@jowyang), says: "You should only follow people who you trust, you think are interesting, or that you learn from".  A quick note to that affect (ie, I think you're interesting and would like to hear what you have to say) can have high-impact. There's also a decent chance they'll follow you back.  Which means they'll see those nifty social media enabled job postings you're getting out there.... and spread them across their Twitterverse...