Ahmadiyya as a Cult
Common Cult Characteristics
Lifton's Criteria of Thought Reform and the Qadiani Ahmadiyya
Judgements, Excommunication and Pardon
The Ahmadiyya have a court system for both civil and criminal offences. In addition, a person can be ex-communicated without going through this court system. After excommunication, the only option is for 'pardon' by the Khalifa, who is the original ex-communicator. In the past, they would be blocked from entering a Qadiani mosque, but this has now changed in Western countries.
Full Discussion: Excommunication and Ostracization
Examples of 'pardon':
The real number is somewhere between 1.5 and 2.0 million. Wolfram Alpha Computational Engine supports this, based on worldwide census data (retrieved December 2010):
Video of changing numbers over the last decade or so:
Relations with Mainstream Muslims
Prohibition on mingling with Muslims, as far back as May 1915, and practiced to date:
SOME INSTRUCTIONS FOR THE NEW AHMADIS
"Since the Promised Messiah was a messenger of God and the denying of the Apostles of God is a dangerous boldness and deprives a man of faith hence according to the Quran, the Traditions of the seal of the prophets and the sayings of of the Promised Messiah, it is the duty of every Ahmadi that he should only pray under the leadership of Ahmadi Imams only. But in those places where Ahmadi Imams can not be found, he should offer his prayers alone and should pray to God to give him a Jamaat ot Society of his own, because a true believe can never remain alone. Similarily, it has been prohibited that Ahmadis should give their daughters in marriage to non-Ahmadis, for wives are generally influenced by their husbands and thus make it is making a soul apostate. Likewise, Ahmadis should not attend the funeral services of non-Ahmadis, for it would amount to interceding with God for a man who has proved himself an enemy by denying and opposing the Promised Messiah" (Review of Religions, May 1915)
Also see:
Strange Pseudo-Science
Note: While Lahoris appear less of a cult in some aspects, their adherence to the 'sacred science' of their common founder, Mirza Ghulam Ahmad, would tend to still classify them as such.