I think that if you check out the specs at www.adobe.com, you will see that
there are two qualifications for the "academic" version - a registered
student, or credentialed teacher, and that the progam is NOT used for
commercial purposes.

Many generations ago, the academic versions did not offer the same upgrade
path, but I believe that that has since changed.

I'd suggest reading the license section closely and not rely on what some
seller is telling you.

Hunt

Academic versions may have reduced documentation, especially in paper form.

No (legally) commercial commercial use.

May be restricted upgrade path.

Not for general sale, only for (in theory) students.
This link (Adobe) may help
http://www.adobe.com/education/purchasing/qualify.html

Richard

If it activates its yours to do with as you wish.
It is highly unlikely, but not impossible, that the upgrade version of CS3
will not recognize your academic version of CS2 and not install or activate
as an upgrade. Anyway, if you are eligible for one academic version you will
surely be able to get the next upgrade at the academic price. Adobe knows
that.
Every academic software package I have ever used, all legitimate, have been
fully functional and upgradeable but my versions of Photoshop were not
obtained as Academic packages.
The "not for commercial use" is meaningless twaddle and Adobe knows it.
Adobe has no way to police what you do with the software nor does it clearly
have an inherent right to do so regardless of what is posted on its web
site. The definition of "commercial" is too vague. A teacher earning money
instructing off that academic copy  could be prosecuted for commercial use
of the software. There is no way to prove that an image has been altered
specifically with Photoshop although that the image has been processed can
be detected.
Can Microsoft restrict the use of its Student/Teacher version of Office to
use for term papers? Why would it want to?
Academic pricing is really a marketing tool to try to hook beginning users
on a specific product that they will continue with down the inevitable
upgrade path. Adobe knows this full well or it would not offer an Academic
package.
If one can legitimately obtain a copy of an earlier version of Photoshop,
and their are legal ways to do so, then one is eligible for the upgrade
priced package anyway.

To buy the academic version you have to provide either a student or a
teacher's ID.

If you don't have that, you're going to have to buy retail or find some
way to qualify for another discount.

The academic version is indeed identical to the retail, except the
About Box says "Educational Version" on it. Otherwise, all functions
are the same, and the licensing (e.g. what you can use it for) is the
same.

The academic version is also eligible for future upgrades, and you can
continue to use it after you are no longer a student. In other words,
aside from the price and the purchase requirements, it's the same
product.

The academic pricing is only available to students, and you must
provide proof of eligibility to the seller. I bought mine through
www.academicsuperstore.com using my current college student ID.