A lot of comments in this thread are misleading. What the Supreme Court has done is that it has expanded the interpretation of an existing Fundamental Right ('Right to life') to include a 'Right to Privacy'. Now this means that if any law is made that infringes on an individuals privacy then it'll be tested for reasonableness.

So before this judgment, the legislature could have for example made a law requiring all internet activity to be reported to the government or criminalized homosexuality (existing law) and anyone challenging the law could not claim that the law violated his privacy as such a right was not recognized.

After this judgment, such an argument could be made and the courts would test whether the violation of one's privacy is a reasonable restriction or not. So a law requiring you to have number plates on your car to be captured by traffic cams, or KYC norms for Bank accounts, reporting of your financial data to tax authorities could be held to be a reasonable restriction whereas laws such as criminalizing one's sexual orientation could be held unreasonable.

What prompted this constitutional reference was the governments 'Aadhar Scheme' which compelled 1.2 billion citizens to hand over their private biometric data to the government if they wanted to claim any government services. This judgment provides the test to be used while deciding whether the law and its applications are constitutional. Most likely the scheme will not be struck down in total but specific instances will be tested on a case by case basis. (eg. Aadhar can't me made compulsory for getting health services but can be made so for a Gun Licence as the latter seems reasonable but the former may not)