Truecaller is a global phone directory application for smartphones and feature phones, and accessible via a Web site, It finds contact details globally given name or telephone number, and has an integrated caller ID service using Crowd sourcing to achieve call-blocking functionality and social media integration to keep the phonebook up-to-date with pictures and birthdays
Never pick up an unwanted call
Truecaller gives you immediate access to an expansive list of top spammers, allowing you to quickly block calls from all numbers reported as spam. Truecaller users work hard to crowdsource information and report spammers in order to make the entire Truecaller community smarter!
See Who’s calling
Help guard your most personal accessory, your mobile phone, by instantly knowing who is calling before you pick up. Truecaller gives you the knowledge of who is trying to get in touch with you even if the number is landline, mobile or pre-paid.
Search Numbers and Names
Searching for any number or name becomes easy with Truecaller. You can find businesses, financial institutions, or friends in the Truecaller community easily through the search function. Truecaller users will be notified when someone requests their number, and have the option to approve any request that comes through.
Add pictures and contact information
You can easily keep your contact list updated with friends’ profile pictures and status updates by choosing to source information from popular sites like Facebook, LinkedIn, and Twitter.
One major benefit of this is, I could figure out the caller details, and if it’s a telemarketing call, You don’t need to call back. Truecaller is one very popular service, which let you find the details of unknown mobile numbers. Best part is, Truecaller is also available online, and they have mobile apps for all popular mobile OS platform.