The act of writing your e-mail address (or mobile phone number) on sandy beaches, in the hope of attracting an interesting response. Short descriptions of age and gender (i.e. M30) often accompany such postings. Often, the practice is abused by providing the contact details of an unwitting 3rd party.
Oh my Gosh! I was beach posting Tammy's email addy last week and now she's got a cyber stalker.