As soon as you can get someone CONSUMING your information. ie Reading your MarketWatch Newsletters and updates of new listings, looking forward to your new updates...using your website to search properties, you've made a connection with them.
If they're not consuming your information...they're not connected.
That's why it's so important to make sure your information gets "heard" over all the noise that's going on in their lives.
Mail has a bigger impact than email. You get less of it in general...and certainly less PERSONAL mail (especially in a BIG envelope) about things you're interested in.
At the very least...even if you're emailing MarketWatch...you want to send people some kind of mailing that lets them know you're on the job...the job of being their Realtor or Lender.
Once you're committed to being their Realtor or Lender, let your actions speak louder than words.
Even if you're in competition, the one who serves the most...wins.