Not that long ago, people declared their political affiliation (Republican, Democrat, Whig...) and religious affiliation. Obituaries often carried this information.
The trend toward praising and thanking God is a personal thing that on-line communities allow them to do without some naysayer coming along and telling them to stick it. The anonymous nature of the internet has caused many of them to "come out of the closet" and declare their religious convictions.
You see some of it in this forum, as well.