[Phil] In the 'following someone annoyingly' sense. Why, what other senses are there? ;o)

[Irouléguy] Doesn't the prefix 'en-' mean something closer to 'to make'? (Enlarge - to make sth large).
Actually, the example that made me think that was ennoble - to make noble.

I have on my lap a big Chambers Dictionary:

en- prefix
1) in words derived from Latin through French (a)used to form verbs with the sense of in, into, upon; (b) used to form verbs with the sense cause to be; (c) used intensively or almost meaninglessly;
(2) in words derived from Greek used to form verbs with the sense of in.

I can't think of any for sense (c)...

(Knobbly) I think enliven could fall into your category (c). Liven would do on its own ( = to make lively).

The Simpsons also introduced "enbiggen", iirc.

[CdM] Wasn't that EMbiggen? As in, "A noble spirit embiggens the smallest man" or something to that effect?

[penelope] "To hold or fasten with a mechanical device", apparently. >-]

It's so nice to see grammaticalisation and form-function reanalysis in progress. Errr... I think.

House news - we now have a phone, the main delay caused by the engineer not knowing where a big pipe of wires came out. Broadband apparently appeared first thing this morning, but since I had to come into work to read my email I didn't know about it then. (Actually, given that we've just had a system "upgrade" here, it might have been better to have stayed at home in any case). First major disaster was the downstairs neighbour complaining of water coming through our ceiling. We had a plumber/odd-job-man come out Saturday morning and spend three hours under the bath fixing the makeshift repair that the previous owner must have done about, oh, three or four days before moving out. Nice welcome present for us, oh yes. Anyway, should be fixed now; no all we need is for someone to plumb the gap that subsequently appeared in my bank account.

+w

Knobbly] I must admit i didn't look it up - I just went off the sense of most of the 'en-' words I could think of. I still can't think of an example for making smaller, though.
Another contender for your sense c) is 'tangle' and 'entangle', though according to Webster-Merriam Online 'tangle' is an Anglo-Saxon shortening of an old French verb 'entangler'.

*waves red rag* Can I argue for 'to Google' as one useful example of verbification? I can't think of an alternative that isn't a clunky noun-phrase - to look up on Google, to research on Google, to scope (out) on Google, etc.

I think "to Google" as a verb for "to search on Google" is OK, but only informally. I use it myself. However, it has become synonymous with "to search on the Internet, regardless of search engine used" which plays into the hands of those evil corporate types.

It has, of course, an friend in "to hoover."

Right on cue, Slashdot reports that "Google Sends Legal Threats to Media Organizations" over the use of its name as a verb for internet searces. See here.