The shift to electronic submissions for literary journals has reached a tipping point — more than 50% of journals are accepting some form of electronic submission. What this means is that the pressure has shifted off the journals accepting electronic (the pressure of a expanding slush pile), and has shifted to the journals who still only accept snail mail submissions (the pressure of seeming archaic).
For some sample statistics, I'll use the categories in my Rankings of Literary Journals, which includes almost exclusively print journals — these percentages would rise dramatically if online journals were included.
In the Extremely Competitive category, 4 out of 7 journals accept online submissions (57%).
In the Highly Competitive Category, 8 out of 17 accept online submissions (47%).
In the Strongly Competitive Category, 29 out of 52 accept online submissions (56%).
One factor that's speeded up the recent shift to electronic submissions has been Submishmash, which is free, unlike the previous dominant submissions manager provided by CLMP, which charged a licensing fee. Three high profile recent converts to Submishmash are Harvard Review, North American Review and New England Review.
Thankfully — for writers — only a small minority of journals have begun charging for electronic submissions, although I think this could change in the future.
If you want a list of journals accepting electronic submissions, check out my list on the left. Of course, if journals keep on permitting online submissions at this rate, I'll have to dismantle the list and replace it with the much shorter list of journals that don't accept online submissions.