I am sure that many readers knows Autodesk.
With their AutoCAD, they monopolized the CAD market, also using tactics like "buy-competitors-and-close-them". Every year they do a new version of AutoCAD, with invisible differences between them, except for the save file format, designed to be not retro-compatible. The update price it is a great deal, just 780 euro (source). Moreover, if you have a full version, you are practically forced to buy an update every 2 years, otherwise you won't be entitled to get the "discount" on the update.

Then, AutoCAD is not available on Macs, because, the price is just 5640 euro for a single-user licence, it is not worthy to do a Mac version: if you can pay 5640 for a license, you can buy a dedicated PC. However, they have several versions of AutoCAD on sale, mechanical, architectural, but the main versions are two:

• "Full" AutoCAD, just for 5640 euro (source)
• Autocad LT, a "light" version, for this reason it is sold for the bargain price of just 1581 euro (source)

The differences between the two AutoCAD are:

1. 4059 euro on the price tag
2. 3d drawings creation
3. Inserting images

So, since for the 3d graphics, there are better softwares, like 3ds max (still bought from Autodesk) o the free Google Sketchup, the only true difference is the possibility to insert images! Yes, you didn't misunderstood! A 2009 software, sold for 1581 euro, cannot import images! Even the most freeware of the freewares, or the most outdated of the WYSIWYG editors can insert images! Even MacWrite from 1984 could handled images.

So, a German firm had an idea: LT Extender, a plugin for Autocad LT, that enabled an "insert images" option  . This plugin was on sale from 2002, and was sold as an "authorized plugin". Of course it had some success .

Recently, since i own a genuine license of AutoCAD, i received an e-mail from Autodesk (click here to read), that, briefly says:

1. They sued the programmer of LT Extender
2. They won and they also got the customers portfolio of the German firm
3. If you bought LT Extender, and they can prove it, you have 60 days to pay 4338 euro and buying a full AutoCAD version with a 30% discount, otherwise they will sue you for copyright violation

Really!!! It says: (in Italian; i cannot find the Legalese text in English, translating in Plain English is senseless)

Gli utenti privati nonché le aziende, i cui collaboratori abbiano utilizzato LT Extender, hanno l'obbligo di rimozione (cancellazione di LT Extender), cessazione e risarcimento danni. Gli amministratori di tali aziende rispondono a titolo personale. Inoltre, l'uso non autorizzato di opere protette dal diritto d'autore è legalmente perseguibile.

Weird!! Why sue the customer??? I agree that Autodesk is entitled to a compensation from LT Extender, but why the customer, that has gave to Autodesk 1581 euro + 780 euro every year for updates, must pay a compensation????