Is patent helps software development ?

Previosly I had made a post on software piracy done or being done by some file sharing sites and wares sites. Recently I could see a news which is about software patents ie. about the after effects of legal notices sent by certain firms. some cases are detailed below :
1. Many iPhone app developers withdrew their apps from US app stores, in light of receiving patent infringement notices from a firm named Lodsys, which claims to have patent for in-app billing.

2. Oracle sued Google claiming Android infringes Java technology patents (which Oracle got after acquiring Sun Microsystems) and asking for 2.6 billion dollars as compensation.

3. Kootol Software Limited, a Mumbai based software firm has sent patent infringement
legal notices to 32 companies including Facebook, Twitter, Apple as it has patent over
real-time messaging.

4. Paul Allen's firm sues 11 firms including Apple, Facebook, Netflix for violating its patents in 3 specific areas: attracting user's peripheral attention, alerting users for items of current interest & using a browser to navigate through information.

As per wikipedia, Patents are intended to promote innovation by encouraging the timely disclosure of how to make and use inventions and by protecting investments made to commercialize inventions.

There are good and bad effects in issue patents as far as software developments are concerned. The good thing is that it protects the interest of the institutions /persons who make research and development in software programmes. Other is that if some firms sees any distant similarity with the product of a rival company, they send legal notices as seen above. Defending a patent case is known to be too much costly and certainly it will effect the research of software.

Friends , what do you say ? Patents are doing good in software development? If so what is your suggestion to protect the software development field from unnecessary court cases?

Thanks and regards,