Originally only suggested or mentioned by Keyur of campbx, but now also agreed upon by Virtex, providing a json api implementation offering results by last trade id or last trade timestamp opens up a kind of cost or risk.
Here's discussion with cavirtex.com:
me: Is it possible to query trade history by last trade id or last trade date? See https://bitcointalk.org/index.php?topic=44674.0
cavirtex: No, not currently. It would be possible, but as keyur suggested on the
forum, there is a cost/risk associated with making that available.
Also at this stage, standing up a mirror and implementing exceptions
for the cached data wouldn't likely be worth the cost savings in
bandwidth, unless you had some other argument for creating such an
Currently, we do cache our data and allowing someone to choose the
range would make caching more difficult. Right now, the current
solution of fixed history seems to be within bandwidth limits and is
easily cached (making it easy to process). Compressing it would be an
easier step in your direction. That data would likely compress very
well and if cached, would only need to be done once in a while.
To comment on the post a bit. A proof by anecdote (ie. mtgox and
intersango do it) does not make a solid arguement for it's
implemenation because of counter arguments such as "perhaps they are
not being abused yet?" and the fact that they operate in different
enviroments (as keyur suggested).
Perhaps this issue/concern can be discussed a bit to establish a consensually agreed upon idea on how to best implement a secure, stable method of allowing querying by last trade id or last trade timestamp; one that is not susceptible to abuse?