I actually have never had a job that I did not get in this manner, contract or full time.
Edit: This is with the added addendum that I research the company beforehand, and know their business model and products as well as any engineering stuff they have published/blogged about.
But really it would depend how you make contact. If you simply send a CV saying I want a job, you'll get the brush off.
The exceptions are;
1) If I've worked with someone even if it's not a close relationship. Then I'm much more open to chatting about something coming up or sending someone to a colleague as a recommended known quantity.
2) Send useful information. e.g. Send a document saying something my business is currently doing that I am responsible for and you feel by doing XYZ you could improve this. If its a good idea with realistic implementation I'd likely chat and consider a contract which might lead to something more permanent. This I feel is the best way to approach someone if looking for a job.
Edit: Fixing embarrassingly bad grammar.
As soon as I started hiring at my last company, I got a lot of worthless email. Tons of contacts from companies selling low-rent coding. Randos selling things totally irrelevant. People who sent in resumes apparently without even reading my advertisement. Kooks.
That left me generally ill-disposed to anything that looked spammy, thoughtless, or clueless. So if you're going to write directly, make it worth the reader's time. Your email should be smart, clear, and short. You should have read and understood absolutely everything publicly available. And you should be either asking or telling me something that is not already obvious.
Best of all, of course, is that you get somebody to make an introduction. If somebody I already respect is willing to vouch for you, that's worlds better than a cold email out of the blue.
What leads me to believe this is that I never had much trouble finding jobs before it became common to apply for them online.