Hypothesis

Using web to send SMS is not good for the mobile phone user who hate to receive promotional advertisement.

Your friend or known person sending SMS from web to your mobile phone at free of cost. Beware that the web site offering such service is to collect your mobile phone number. Do you thing you are offered a free service or somebody running charity to send SMS from web at free of cost?

Offering free SMS sending service from web may be a business to collect valid mobile phone numbers and sell it to advertisers.

I started receiving lots of promotional SMS and ad calls when my friend starting using 'some' web site to send SMS to me. I was wondering how do they know my mobile phone number.

I changed to new number. I did not receive any promotional SMS. Again my friend send sms to my new number through a web site which offers free SMS service. I started receiving promotional SMS and ad calls again.

Do you know how much it costs to send SMS from web? Web to SMS service is not free or cheap. It has cost applicable as sending SMS from mobile phone directly.

'Intelligent' business people are using the web to collect active mobile phone number to sell.

Your mobile phone number is a commodity to sell in 'Web to SMS' realm.

Avoid using 'web to SMS' free services and advice your friends to not to send sms from web.