Conversions have happened and will happen. It has nothing to do with a certain religion being good or bad, how much hard we may try our priests our products of their times and they will use all kinds of things to lure people in becoming part of their religion (as Aparna has pointed out)
There are several things common in Christianity, Islam and Jewish religion.
Similarly, India is the only place in the world that is besides HInduism home even birthplace of Buddhism, Jainism, Sikhism and others. It was the only place where Jews were not persecuted.
Religion is a serious matter, we are too young to comprehend it why cant we stick to common principles that all religions teach? of compassion, humanitarian beliefs and doing what comes naturally to us ie live and let live.
1