I've recently joined OLD (as in, this past week!)...I'm not sure if it's going to be for me. I've received loads of "Hi" messages. One guy that began chatting with me seemed my type, but wasn't asking any questions about me, only answering what I asked him. He gave me his number in case I wanted to text him as he was going out of town (but I wasn't comfortable giving out mine yet), and then shortly thereafter his profile was deleted. 
I haven't contacted anyone first except for two guys - sent a very short message to a nice looking physiotherapist, who did respond...but never bothered to reply again when I sent out something a little longer (although my message was only sent yesterday so maybe he will get back to me...but he's been online since then so I'm guessing he won't if he hasn't already).
And haven't heard anything from the other guy at all and he hasn't even viewed my profile (although it looks like he has been online since I messaged him), which I find weird as I do think he would have at least looked at my profile, even if he ultimately decided not to return the contact.
I also made the mistake of responding to a guy 6 years younger than me because he seemed interesting...and surprisingly got this really long and thoughtful (impressive) email back, which makes me feel like I'd want to correspond but I already know it's not a good idea as there are some fundamental incompatabilities there.
Oh...and let's not forget the guy who keeps writing "hey there," with nothing further to add even when prompted. He's now been blocked and deleted.
Maybe I'll get used to it, but so far I'm not really liking it!