Tony
Some of the problems have been highlighted above but it can go much further that as Michael Horner indicates.
Just to expand the scenario a bit;
Name and phone number not really a problem, but then we can expand the information a bit. Land line phone number gives us the area code and the posting gives areas of interest with specific equipment mentioned. With a little bit deeper digging it is almost a certainty that one can find all the Joe Bloggs in that area. Couple that to his phone number and there is a fair chance you have the address. Go to street maps and usually you can walk up to almost the front door, take a good view of the front of the premises and what there is in the area of interest. Switch to satellite view and any sheds etc, size of garden, any pathways to the rear of the property or possible routes in/out can be assessed.
Now we have a total picture of where that person lives and at least one of his interests; trawl through other sites and it could well reveal other interests and whether he has any other assets i.e. model steam locos etc. A little more digging and you see whether he is likely to be retired or not and who else plus their ages are likely to be resident at that address.
All this can be done anonymously from your desk chair while drinking a cup of tea plus a small outlay to the odd website for data. Using this information and a false utilities bill or bank statement and it may be possible to make various financial agreements for which poor Joe Bloggs will be responsible.
All this from a name and a telephone number posted on a website.
It may a bit melodramatic but it gives you an idea of how a couple of scraps of what appears to be innocuous information could lead to. There have been posts on this site about locos being stolen from people's workshops and it is indeed feasible that the thieves used information gleaned from engineering/hobby sites to identify their target.
Hope this helps to explain why I made the comment about using the PM on this site
Martin W
PS
No I am not paranoid but I like to keep some of my personal details to myself though it is getting more difficult.
Edited By Martin W on 02/10/2016 16:48:22