Deciding a license for open source software is always difficult. Legal mumbo jumbo is not the strong point for most programmers. Therefore, let me explain the spirit of the licence before moving on to the legal stuff.
As equanda is open source, the choice was for a copyleft license (see http://www.fsf.org/licenses/licenses.html#WhatIsCopyleft). This means that the code is open source, and it cannot be closed.
That is, all modifications to this software need to be published (and need to be open source again).
The best known copyleft license is probably GPL, but that is known to be infectious, as it strictly disallows using equanda as part of something which is not entirely GPL.
equanda is intended for the delopment of enterprise level application, and thus it should be suitable for all kinds of commercial applicatons. As a result, using GPL was a strict no-no.
Not wanting to write yet another open source license, MPL seems like the best choice.
Of course, as equanda is open source, we also want to encourage the use of equanda in other open source projects. A lot of open source software is licensed as GPL or LGPL, but the free software foundation says MPL is not compatible with these licenses (see http://www.fsf.org/licenses/license-list.html).
The people at Mozilla were also aware of this problem, and solved this by triple licensing (for background see http://www.mozilla.org/MPL/relicensing-faq.html). In short, the code is licensed using MPL, but the user may choose to replace the license by either GPL or LGPL.
The full applicable license texts :
All code which is added in equanda needs to be triple licensed like this, or have another license which is compatible (more liberal) with this triple license.
_Addendum_ : equanda contains quite a few templates which generate code. While these templates fall under the triple license, the generated code does not and can be modified and used at well (so also in commercial products, without the need to publish the changes).