is there useally an actual date when two people become boyfriend and girlfriend?

[♬♫♬♪♩♪♬]

i never had a proper relationship but a few people i know have dates posted on their facebook pages as to how long they have been together?

i thought relationships developed over time and not one exact date?
can somebody enlighten me a little bit?.
is there a usually a date where peoples go from meeting each other to actually going out?

[Buffpap]

When it is mutually agreed that they are exclusive.

[Finny Macgee]

Yes; May 22nd.

[you dont know me]

Usually there is a period where you are "just dating", and getting to know one another. Then one or the other decides to make it more serious, so they ask them to become exclusive, and on that day is usually the first day of the relationship.

Exclusivity is the key, really. The day you are officially off the market to anyone else.