I do discourage any face to face meetings with people we meet on a forum. but, there are times it can be very constructive and beneficial, perhaps even necessary.
Caution is the key and of the utmost importance. I am aware that genuine friendships do occur on forums, but remember if it is a genuine friendship all parties will agree to conditions that are safe and halal. If it does appear that a face to face is possible and it is something worth pursuing, never agree to meet alone and be certain any meeting is in a public location. Verify the identity of the person prior to any meeting, agree to only meeting in public, agree to meet only with a person of the same gender.
If for some reason there is a legitimate reason for people of the opposite gender to meet, be certain that the female member is accompanied by an older male relative. Keep everything halal.
Never assume that because somebody told you something that it is true. Ask pertinent questions and verify all answers before agreeing to a face to face meeting. Also be certain that their is a purpose for the meeting. Simple desire to put a face with a name is not sufficient reason.
The word Caution can not be said enough.
Also be certain that if you are the one initiating the reason for the meeting, that you do your utmost to assure the other person, you are who you claim to be and give the person sufficient information and time to verify anything you have said.
Better to always keep things on the side of your safety, rather than let your thoughts of meeting a new friend end up as a disappointment or even as a danger.
Remember, nearly everything you would hope to accomplish by a face to face meeting can be done through mail, PMs or telephone. Use those as your primary options if contact is needed and resort to face to face meetings only if there is something that can not be done by any other means.