Google+ allowed to post via SMS right from the beginning but this feature was available only in 2 countries i.e United states and India. Now this feature is available in around 43 countries.
Google+ via SMS numbers list
Google+ sms numbers (for 43 countries)
The list of 43 countries, carriers supported and their SMS numbers are listed in the table below (Source: Google+)
| Country | Carrier | SMS number(s) |
| Afghanistan | AWCC | 2125400 |
| Afghanistan | Etisalat | 8080400 |
| Afghanistan | Roshan | 4664400 |
| Algeria | Nedjma | +213558996400 |
| Angola | Unitel | 46645400 |
| Bahrain | Viva | 87700400 |
| Bahrain | Zain | 94004400 |
| Benin | Moov | 95650400 |
| Cambodia | Smart | 1000400 |
| Cameroon | MTN | 8741400 |
| Cameroon | Orange | +23798008301 |
| Congo, Democratic Republic | Vodacom | +243822063400 |
| Congo (DRC) | Vodafone | +243822063400 |
| Cote D’Ivoire | MTN | 4442400 |
| Cote D’Ivoire | Orange | 2258500 |
| Cote D’Ivoire | Moov | 41918400 |
| Egypt | Mobinil | 34400 |
| Ghana | MTN | 1980400 |
| Ghana | Tigo | 8300 |
| Ghana | Airtel | 5400 |
| Guinea | Orange | 500000400 |
| India | All carriers | +919222222222 |
| Indonesia | Axis | 71400 |
| Indonesia | Hutchison | 4665400 |
| Indonesia | Indosat | 367400 |
| Indonesia | Telkomsel | 4664400 |
| Indonesia | XL Axiata | 94640400 |
| Iraq | Zain | 2601400 |
| Israel | Orange | 1000400 |
| Israel | Pelephone | 10400 |
| Jordan | Umniah | 99813400 |
| Jordan | Zain | 909070400 |
| Kazakhstan | GSM Kazakhstan | 30400 |
| Kenya | Airtel Kenya | +254786100400 |
| Kenya | Safaricom | +254700999400 |
| Kenya | Yu | +254754001400 |
| Kenya | Orange | 10400 |
| Kuwait | Viva | 5078400 |
| Kuwait | Wataniya | 1971400 |
| Kuwait | Zain | 898400 |
| Kyrgystan | Megacom | 46245400 |
| Liberia | Cellcom | 8400 |
| Malawi | Airtel Zain | +265991903400 |
| Malawi | TNM | 80400 |
| Malaysia | Digi | 222350400 |
| Malaysia | Maxis | 260060400 |
| Maldives | Dhiraagu | +9604664400 |
| Maldives | Wataniya Maldives | 4645400 |
| Morocco | Inwi | 333400 |
| Mozambique | Vodacom | 8418400 |
| Niger | Orange | 91995268 |
| Nigeria | Airtel | +2348021600400 |
| Nigeria | Glo | 20202400 |
| Nigeria | MTN | 40700 |
| Nigeria | Starcomms | 33166400 |
| Nigeria | Visafone | 610400 |
| Pakistan | Mobilink | 2434400 |
| Philippines | Globe Telecom | 2662400 |
| Philippines | Smart Communications | 4664400 |
| Philippines | Sun Cellular | 22020400 |
| Saudi Arabia | Mobily | 611011400 |
| Saudi Arabia | Saudi Telecom Company | 88555400 |
| Saudi Arabia | Zain | 710466400 |
| Senegal | Orange | +221774699400 |
| Senegal | Tigo | 22408400 |
| Sierra Leone | Comium | 60400 |
| Sri Lanka | Dialog | 4664400 |
| Sri Lanka | Mobitel | 89000400 |
| Sri Lanka | Etisalat | 103200400 |
| Tanzania | Tigo | 46400 |
| Tanzania | Vodacom | +255766790400 |
| Thailand | DTAC | 42662400 |
| Thailand | TRUE | 47640400 |
| Tunisia | Tunisiana | 871222400 |
| Tunisia | Orange | 871818400 |
| Uganda | MTN | 902801400 |
| Uganda | Orange | +256790791900 |
| Uganda | Uganda Telecom | +256715887400 |
| United States | All carriers | 33669 |
| Uzbekistan | Ucell | 45400 |
| Vietnam | Vinaphone | 9666400 |
| Zambia | Zamtel | 3566400 |
Besides 43 countries, sms commands are supported in 9 languages i.e english, french, spanish, portuguese, arabic, hebrew, swahili, indonesian and thai.
There are millions of smartphones that have the capability to access google+ via browser and google+ app on iphone and android phones. But at the same time there are billions of devices which are not smartphones that have SMS / texting capability. This Google+ sms feature would give them the opportunity to connect with the world and share their thoughts.