Re: something has happened to date, when added to the statistics.

according to the records in the database it happened 03/07/2013:

INSERT INTO `piwik_log_visit` (`idvisit`, `idsite`, `idvisitor`, `visitor_localtime`, `visitor_returning`, `visitor_count_visits`, `visitor_days_since_last`, `visitor_days_since_order`, `visitor_days_since_first`, `visit_first_action_time`, `visit_last_action_time`, `visit_exit_idaction_url`, `visit_exit_idaction_name`, `visit_entry_idaction_url`, `visit_entry_idaction_name`, `visit_total_actions`, `visit_total_searches`, `visit_total_time`, `visit_goal_converted`, `visit_goal_buyer`, `referer_type`, `referer_name`, `referer_url`, `referer_keyword`, `config_id`, `config_os`, `config_browser_name`, `config_browser_version`, `config_resolution`, `config_pdf`, `config_flash`, `config_java`, `config_director`, `config_quicktime`, `config_realplayer`, `config_windowsmedia`, `config_gears`, `config_silverlight`, `config_cookie`, `location_ip`, `location_browser_lang`, `location_country`, `location_region`, `location_city`, `location_latitude`, `location_longitude`, `custom_var_k1`, `custom_var_v1`, `custom_var_k2`, `custom_var_v2`, `custom_var_k3`, `custom_var_v3`, `custom_var_k4`, `custom_var_v4`, `custom_var_k5`, `custom_var_v5`, `location_provider`) VALUES
(902684,	1,	UNHEX('2E9D549075DF8584'),	'08:21:48',	0,	1,	0,	0,	0,	'2013-07-03 01:21:51',	'2013-07-03 01:21:51',	18811,	25284,	18811,	25284,	1,	0,	0,	0,	0,	3,	'www.youtube.com',	'http://www.youtube.com/watch?v=xxx',	'',	UNHEX('16E226947FD44CE9'),	'WI7',	'CH',	'25.0',	'1680x1050',	1,	1,	1,	0,	0,	0,	0,	0,	1,	1,	UNHEX('25C22E21'),	'ru,en',	'ru',	'53',	'Novosibirsk',	55.042000,	82.934998,	NULL,	NULL,	NULL,	NULL,	NULL,	NULL,	NULL,	NULL,	NULL,	NULL,	'novotelecom.ru'),
(902685,	1,	UNHEX('740E721D1EDA8474'),	'05:21:53',	0,	1,	0,	0,	0,	'2013-07-03 01:21:55',	'2013-07-03 01:21:55',	30789,	30788,	30789,	30788,	1,	0,	0,	0,	0,	2,	'Google',	'http://www.google.ru/search?q=http%3A%2F%2Fone_of_my_site%2F',	'http://one_of_my_site/',	UNHEX('E0C7E9D9B43E5B55'),	'WXP',	'OP',	'9.50',	'1024x600',	1,	1,	0,	0,	0,	0,	0,	0,	0,	1,	UNHEX('5BCBA8FF'),	'ru,en-us,en',	'ru',	'32',	'Sosnovy Bor',	61.602001,	80.944000,	NULL,	NULL,	NULL,	NULL,	NULL,	NULL,	NULL,	NULL,	NULL,	NULL,	'sbor.net'),
(902686,	1,	UNHEX('DDA2AC03CF281ADF'),	'05:22:15',	2,	1,	0,	0,	0,	'1970-01-01 00:00:00',	'1970-01-01 00:00:00',	19263,	19262,	19263,	19262,	6,	0,	1,	0,	0,	1,	'',	'',	'',	UNHEX('9E5A7774DF19D2C0'),	'WI7',	'CH',	'27.0',	'1920x1080',	1,	1,	1,	0,	0,	1,	0,	0,	1,	1,	UNHEX('58873FB2'),	'ru-ru,ru,en-us,en',	'ru',	'69',	'Smolensk',	54.782001,	32.040001,	NULL,	NULL,	NULL,	NULL,	NULL,	NULL,	NULL,	NULL,	NULL,	NULL,	'Ip'),
(902687,	1,	UNHEX('45D4906B98C3AE08'),	'12:22:16',	2,	1,	0,	0,	0,	'1970-01-01 00:00:00',	'1970-01-01 00:00:00',	27732,	27731,	27732,	27731,	2,	0,	1,	0,	0,	3,	'www.youtube.com',	'http://www.youtube.com/watch?v=xxx',	'',	UNHEX('2B3BA2FA566CF12D'),	'WI7',	'OP',	'12.15',	'1680x1050',	1,	1,	1,	0,	0,	0,	1,	0,	1,	1,	UNHEX('3E216FF5'),	'ru-ru,ru,en',	'ru',	NULL,	NULL,	60.000000,	100.000000,	NULL,	NULL,	NULL,	NULL,	NULL,	NULL,	NULL,	NULL,	NULL,	NULL,	'transtelecom.net');

Piwik from git

# cat /etc/issue
Debian GNU/Linux 7 \n \l

# uname -r
2.6.32-042stab078.22

# php -v
PHP 5.5.0-1~dotdeb.1 (cli) (built: Jun 20 2013 12:55:16)
Copyright (c) 1997-2013 The PHP Group
Zend Engine v2.5.0-dev, Copyright (c) 1998-2013 Zend Technologies
    with Zend OPcache v7.0.2-dev, Copyright (c) 1999-2013, by Zend Technologies

MySQL version: 5.5.31-0+wheezy1-log through PHP extension MySQLi

I also can not understand what happened...