1. Text-Based Messaging: Traditional SMS is a text-based messaging service that allows users to send short written messages from one mobile device to another.

2. Ubiquity: SMS is universally available on nearly all mobile devices, making it a highly accessible and reliable means of communication. It works across various mobile operating systems and network providers.

3. Character Limits: Traditional SMS messages have a character limit, typically 160 characters. Longer messages are split into multiple SMS messages, which may appear as a single continuous conversation to the user.

4. Cross-Platform Compatibility: SMS messages can be sent and received between different types of mobile devices, including smartphones, feature phones, and even some older mobile devices.

5. Reliability: SMS is known for its high reliability. Messages are typically delivered quickly, and users receive delivery notifications to confirm that a message has been successfully sent.

6. Cost-Efficiency: SMS is often included in mobile plans, making it a cost-effective means of communication. Users typically don't incur additional charges for sending or receiving SMS messages.

Limitations of Early SMS:

1. Text-Only: One of the most significant limitations of early SMS was its text-only nature. Users could send and receive only plain text messages without any multimedia elements such as images, videos, or audio.

2. Character Limits: The 160-character limit posed challenges for users who wanted to convey longer messages. Longer messages were broken into multiple parts, leading to potential confusion and increased costs.

3. No Read Receipts: Traditional SMS lacked the read receipt feature commonly found in modern messaging apps. Users couldn't easily determine whether the recipient had read their message.

4. Limited Formatting: Early SMS had limited support for text formatting, making it challenging to convey emotions or nuances through text alone. Emoticons and abbreviations became popular to compensate for this limitation.

5. Lack of Group Messaging: Early SMS didn't support group messaging, making it less convenient for sending messages to multiple recipients simultaneously.

6. No Encryption: Traditional SMS lacked end-to-end encryption, which meant that messages were less secure and more susceptible to interception or eavesdropping.

7. No Synchronization: SMS messages were stored locally on the user's device, and there was no synchronization or cloud backup feature. If a device was lost or damaged, SMS messages could be lost as well.

8. No International Support: Initially, SMS was limited to domestic use, and international messaging was expensive and had limited compatibility.

While traditional SMS offered a simple and reliable means of communication, its limitations eventually led to the development of more advanced messaging platforms and apps. These platforms addressed the shortcomings of early SMS by introducing multimedia support, larger character limits, read receipts, end-to-end encryption, cloud synchronization, and a wide range of additional features. As a result, SMS continues to be a fundamental service for basic text-based communication, while modern messaging apps have evolved to provide more comprehensive and feature-rich communication options.