Deoes any email is send when i open drupal webpage first time? I heve a not nice "error/message" from time to time on the bottom of the page... It is sth like this:

SMTP -&gt; get_lines(): $data was "" 
SMTP -&gt; get_lines(): $str is "220 poczta1.www.www.pl ESMTP Postfix " 
SMTP -&gt; get_lines(): $data is "220 poczta1.www.www.pl ESMTP Postfix " 
SMTP -&gt; FROM SERVER:220 poczta1.www.www.pl ESMTP Postfix 
SMTP -&gt; get_lines(): $data was "" 
SMTP -&gt; get_lines(): $str is "250-poczta1.www.www.pl " 
SMTP -&gt; get_lines(): $data is "250-poczta1.www.www.pl " 
SMTP -&gt; get_lines(): $data was "250-poczta1.www.www.pl " 
SMTP -&gt; get_lines(): $str is "250-PIPELINING " 
SMTP -&gt; get_lines(): $data is "250-poczta1.www.www.pl 250-PIPELINING " 
SMTP -&gt; get_lines(): $data was "250-poczta1.www.www.pl 250-PIPELINING " 
SMTP -&gt; get_lines(): $str is "250-SIZE 262144000 " 
SMTP -&gt; get_lines(): $data is "250-poczta1.www.www.pl 250-PIPELINING 250-SIZE 262144000 " 
SMTP -&gt; get_lines(): $data was "250-poczta1.www.www.pl 250-PIPELINING 250-SIZE 262144000 " 
SMTP -&gt; get_lines(): $str is "250-VRFY " 
SMTP -&gt; get_lines(): $data is "250-poczta1.www.www.pl 250-PIPELINING 250-SIZE 262144000 250-VRFY " 
SMTP -&gt; get_lines(): $data was "250-poczta1.www.www.pl 250-PIPELINING 250-SIZE 262144000 250-VRFY " 
SMTP -&gt; get_lines(): $str is "250-ETRN " 
SMTP -&gt; get_lines(): $data is "250-poczta1.www.www.pl 250-PIPELINING 250-SIZE 262144000 250-VRFY 250-ETRN " 
SMTP -&gt; get_lines(): $data was "250-poczta1.www.www.pl 250-PIPELINING 250-SIZE 262144000 250-VRFY 250-ETRN " 


The strange thing is that this happens only from time to time and is displayed on the main page at the bottom (usser is not logged in). When user visit the page again (F5), information disappear, does that mean that the web template  have hidden code to send an email about web template usage?
You have the SMTP module set up for debug mode, so it prints the protocol exchange details for every email sent. In addition, poormanscron (which is default in Drupal 7) is being triggered by the page request. 

If you turn off the debug option for SMTP those lines will no longer appear. Also you may want to set up an automated cron job so cron runs in the background rather than when users are making requests.